Crane

ABSTRACT

A crane wherein the lower end of a boom is so pivoted as to permit not only the slanting motion but also swinging or revolving motion of the boom, and one rope is employed not only for slanting the boom and but also for hoisting the loads while the swinging or revolving motion of the boom is effected by a single pressure cylinder whose leading end is coupled to the mid portion of the boom.

llnited States atent n91 Tanabe CRANE [76] Inventor: Jiro Tanabe, No. 7. 3-chome, KandaOg awa-cho, Chiyoda-ku, Japan 22] Filed: Apr. 23,1971

21] Appl. No.: 136,816

[30] Foreign Application Priority Data Ap. 24, 1970 Japan ..45/35299 [52] US. Cl. ..2l2/58, 212/3, 212/66 [5 l 1 Int. Cl v ..B66c 23/06 [58] Field of Search, ..2l2/3,58, 35,66

[56 References Cited UNITED STATES PATENTS 412,525 lO/l889 McBride ..2l2/66 FOREIGN PATENTS OR APPLICATIONS 166.725 4/l959 Sweden ..254/l50 Pfillldl'y ExaminerHarvey C. Hornsby Anm'neyScrivener, Parker, Scrivener & Clarke [57] ABSTRACT A crane wherein the lower end of a boom is so pivoted as to permit not only the slanting motion but also swinging or revolving motion of the boom, and one rope is employed not only for slanting the boom and but also for hoisting the loads while the swinging or revolving motion-of the boom is effected by a single pressure cylinder whose leading end is coupled to the mid portion of the boom.

4 Claims, 7 Drawing Figures Patented April 24, 1973 3,729,100

2 Sheets-Sheet 1 INVENTOR J IRO TANABE /WW #X/MAW ATTORNEY$ Patented April 24, 1973 3,729,106

2 Sheets-Sheet 2 INVENTOR J I R0 TANABE ii/mm fm/ w z/Wmf ATTORNEYS CRANE DETAILED EXPLANATION OF THE INVENTION The present invention relates to a crane for ships and the like and its object is to provide an improved crane which is simple in construction and is capable of easily horizontally moving the loads.

The crane according to our invention is characterized in that a single pressure cylinder is coupled to a boom pivoted so as to slant or swing vertically (in a vertical plane containing the axis of a derrick post) and to swing about the axis of said derrick post in such a way that said boom may be swung about the axis of said derrick by said pressure cylinder, and one end ofa slanting rope whose other end is fixed to the leading end of said boom and one end ofa hoisting rope whose other end is fixed to a drum of hoist are fixed to another drum in such a way that both of said ropes may be wound around said another drum in the opposite directions.

The present invention will be described in more detail with reference to the accompanying drawing illustrating the preferred embodiment thereof.

FIG. 1 is a side view of a crane in accordance with the present invention;

FIG. 2 is a top view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a diagram illustrating the arrangement of ropes;

FIG. 5 is a perspective exploded view of two-gangedsheaves attached to the leading end ofa boom; and

FIG. 6-(a) and FIG. 6-(b) are side and front views respectively illustrating how the lower end of the boom is pivoted.

In the drawing, reference numeral 1 designates a boom; 2, a derrick post; and 3, a pressure or power cylinder (hydraulic or pneumatic cylinder or cylinder of the type in which a threaded rod is moved into and out of the cylinder). As best shown in FIG. 6, the lower end of the boom 1 is so pivoted by universal means that it may swing not only about a pivot 4 but also about a pivot 5 which is at a right angle relative to the pivot 4. It is therefore seen that the boom 1 may slant or swing about the pivot 4 in a plane vertical to the deck and may swing about the pivot 5 in a plane at an angle relative to the above described vertical plane. The lower end of the pressure cylinder 3 is also pivoted in the same manner as described above and the leading end 3' of the cylinder 3 is coupled to the boom 1 so that the leading end 3' may follow the movement of the boom 1.

The main function of the pressure cylinder 3 is to swing the boom 1 in the inclined plane whereas the slanting motion or swing of the boom in the vertical plane and hence the hoisting of a cargo are accomplished by ropes.

As best shown in FIG. 4, two ropes are used. One rope a is for slanting or swinging the boom 1 in the vertical plane whereas the other rope b is for hoisting the loads. As shown in FIG. 4, three-ganged-sheaves S S and 8 are fixed to the upper portion of the derrick post 2 and two-ganged-sheaves S and S as shown in FIG. 5 are fixed to the leading end of the boom 1. The rope a has its one end fixed to the leading end of the boom 1 and is wrapped around the sheave S and wound around a boom pivoting drum D One end of the other hoisting rope b is fixed to the drum D and the rope b is wound around the drum D in the direction opposite to that of the rope a. The rope b is wrapped around the sheaves S and S reversed in direction by a hoist sheave 6 fixed to a hook, wrapped around the sheaves S and S and wound around a hoist drum D Referring to FIG. 5, a fitting 7 is rotatably fitted over the leading end of the boom 1 and the sheaves S and S together with rope connectors 9 are fitted over shafts 8 extending horizontally from both sides of the fitting 7. Since the essential feature of this arrangement is that the sheaves S. and 8;, may have their angular positions relative to the boom I changed freely, it is understood that other suitable sheave mounting arrangements may be employed as needs demand.

The two drums D and D are intercoupled to each other through the conventional difference gear or clutch so that by a motor of the drum D only the drum D or D or both of the drums D and D may be driven. It is of course possible to drive the drums D, and D by individual motors, but it is more economical and easier to drive either or both of the drums D and D by a single motor.

When the drum D is driven, the load may be lifted or lowered whereas when the drum D is driven, the boom 1 may be swung or luffed while the load is maintained at a constant level or height. When both of the drums D and D are driven simultaneously, the boom is swung or luffed while the load is lifted.

One of the most important features of the present invention resides in the fact that the load may be moved horizontally at a desired level or height regardless of the swinging or revolving of the boom 1. That is, when the drum D is driven so as to wind the rope a, the load is lifted. In this case, the rope b is unwound because it is wound around the drum D in the direction opposite to the direction of winding of the rope a, so that the load may be maintained at a desired level while it is moved horizontally even when the boom 1 is raised or swung upwardly.

On the other hand when the rope a is unwound from the drum D so that the boom 1 is lowered or swung downwardly, the rope b is wound around the drum D As a result the load may be maintained at a desired level.

As described above, upon the vertical swinging of the boom 1, the hoisting rope b may be wound or unwound so that the load may be horizontally moved without changing its level. In addition, the rotational force of the drum may be maintained almost constant even when the load is lifted. Since the ropes a and b are wound around the drum D in the opposite directions, the drum D may be driven with a relatively small force or power. A partition wall or the like may be provided on the drum D at the center thereof so that the two ropes a and b wound around it may be completely separated from each other. I

The hoisting rope b supports the loads while the rope a supports the boom I so that almost no force acts upon the pressure cylinder 3. Therefore, the boom 1 may be swung transversely or revolved by the pressure cylinder 3 with a small power through a wide angle 0 shown in FIG. 2.

From the foregoing description, it is seen that the crane or derrick in accordance with the present invention is simple in construction, low in cost and simple and reliable in operation. In addition, the load may be horizontally moved and only a pressure cylinder 3 with a relatively small power is required.

What is claimed is:

1. A crane for hoisting and transporting a load relative to a fixed support, comprising a vertical derrick post (2) supported at its lower end by the fixed support;

a boom (1);

pivot means (4, 5) connecting said boom at one end with said support adjacent said derrick post both for pivotal movement in a vertical plane that contains said derrick post and for swinging movement generally about the axis of said derrick post; said boom having a load sheave at its outer end means including a pressure cylinder motor (3) connected between said boom and the fixed support for swinging said boom generally about the axis of said derrick post;

first and second drums (D D each rotatably connected with said support;

a first rope (a) connected at one end with the free end of said boom, the other end of said first rope being wound upon said second drum;

a hoist sheave (6) adapted for connection with the load;

a second rope (b) wound at one end upon said second drum in the opposite direction as said first rope, said second rope extending over said load sheave and around said hoist sheave and being wound at its other end on said first drum;

means for driving said first drum to vary the height of said hoist sheave relative to the free end of said boom;

means for driving said second drum to pivot said boom in a vertical plane while maintaining said hoist sheave at a constant height relative to the support; and

means for driving said first and second drums simultaneously both to pivot said boom in a vertical plane and to vary the height of the hoist sheave relative to the fixed support.

2. Apparatus as defined in claim 1, wherein said pivot means includes universal means defining a horizontal first pivot axis (4), and a second pivot axis (5) normally to a plane that contains said first pivot axis.

3. Apparatus as defined in claim 1, and further including a three-gang sheave connected with the upper portion of the derrick post and a two-gang sheave adjacent the free end of said boom, said second rope extending around both sheaths of said two-gang sheaves and two sheaves of the three-gang sheaths, said first rope extending around the remaining sheath of said three gang sheath.

4. Apparatus as defined in claim 1, wherein said first and second drums are colinearly arranged, and further wherein said second rope is wound on said first drum in the same direction that said first rope is wound on said second drum. 

1. A crane for hoisting and transporting a load relative to a fixed support, Comprising a vertical derrick post (2) supported at its lower end by the fixed support; a boom (1); pivot means (4, 5) connecting said boom at one end with said support adjacent said derrick post both for pivotal movement in a vertical plane that contains said derrick post and for swinging movement generally about the axis of said derrick post; said boom having a load sheave at its outer end means including a pressure cylinder motor (3) connected between said boom and the fixed support for swinging said boom generally about the axis of said derrick post; first and second drums (D1, D2) each rotatably connected with said support; a first rope (a) connected at one end with the free end of said boom, the other end of said first rope being wound upon said second drum; a hoist sheave (6) adapted for connection with the load; a second rope (b) wound at one end upon said second drum in the opposite direction as said first rope, said second rope extending over said load sheave and around said hoist sheave and being wound at its other end on said first drum; means for driving said first drum to vary the height of said hoist sheave relative to the free end of said boom; means for driving said second drum to pivot said boom in a vertical plane while maintaining said hoist sheave at a constant height relative to the support; and means for driving said first and second drums simultaneously both to pivot said boom in a vertical plane and to vary the height of the hoist sheave relative to the fixed support.
 2. Apparatus as defined in claim 1, wherein said pivot means includes universal means defining a horizontal first pivot axis (4), and a second pivot axis (5) normally to a plane that contains said first pivot axis.
 3. Apparatus as defined in claim 1, and further including a three-gang sheave connected with the upper portion of the derrick post and a two-gang sheave adjacent the free end of said boom, said second rope extending around both sheaths of said two-gang sheaves and two sheaves of the three-gang sheaths, said first rope extending around the remaining sheath of said three gang sheath.
 4. Apparatus as defined in claim 1, wherein said first and second drums are colinearly arranged, and further wherein said second rope is wound on said first drum in the same direction that said first rope is wound on said second drum. 